NONCARDIAC SURGERY IN CHILDREN WITH CONGENITAL HEART DISEASE

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NON-CARDIAC SURGERY IN CHILDREN WITH CONGENITAL
HEART DISEASE
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CHD

• 8 per 1000 live births
• ½ million patients in the US with repaired,
  palliated or unoperated CHD
• Advances in Mx increasing survival
• Trend to early repair
• Anesthetic mx complicated by diversity of CHD and
  wide spectrum of surgeries performed
• CHD adds significantly to the mortality of
  non-cardiac surgery

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SPECTRUM OF CHD
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SPECTRUM OF INTERVENTION

• True correction
• PDA, ASD, some VSD
• Correction with residua
• Some VSD, Coartation of the Aorta
• Correction with sequelae
• TOF, TGA
• Complications
• Arrhythmias or conduction abn. from incisions or
  sutures
• Palliative surgery
• B-T shunt, PA banding
• Cath lab interventions
• Cure or palliation

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ISSUES TO RESOLVE

• Nature of repair
• Age and era of repair
• Ventricular outflow obstruction
• Ventricular dysfunction
• Arrhythmias and conduction abnormalities
• Hypoxemia
• Pulmonary Hypertension
• Endocarditis prophylaxis
• Extracardiac problems
• Monitoring

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NATURE OF THE REPAIR

• ANATOMIC LV to aorta
• RV to pulm artery
• circulation in
  series
• cyanosis corrected
• a) Simple Recon ASD, VSD, PDA
• treat as for
  normal heart
• b) Complex outflow tract (TOF, AS, PS, coarct)
• conduits or baffles (PA)
• septum and AV valve repair

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NATURE OF THE REPAIR

• 2. PHYSIOLOGICAL single or 2 ventricle
• circ in
  series
• cyanosis
  relieved
• significant
  sequelae
• a) Two ventricle repair - RV is systemic
• LV is
  pulmonary
• b) Single ventricle
• TA, HRHS, double inlet/outlet ventricles
• Venous return directly to PA
• success RA to LA pressure grad, n AV
  valve, vent fn
• serious potential problems
  

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AGE AND ERA OF REPAIR

• The trend since the 80s has shifted to early
  definitive repair, without prior palliation
• Also since the 80s TGA is repaired with arterial
  switch, not atrial.

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VENT OUTFLOW OBSTRUCTION

• LV AS, Coarct, Interrupted Ao arch
• fatigue, syncope, chest pain, arrhythmia
• RV TOF, PS, conduit (PA/Truncus/TGA with PS),
  PVOD
• - conduits calcify and narrow
• - ischemic, hypertrophied RV
• - intracardiac defect may relieve pressure

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VENTRICULAR DYSFUNCTION

• Myocardial dysfunction insidious
• May not report symptoms
• History of decreasing exercise tolerance
• Objective evaluation useful
• CAUSES volume overload
• pressure overload
• chronic hypoxemia
• rec/sustained tachycardia

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ARRHYTHMIAS

• major impact after palliation or repair
• life threatening in abnormal heart
• CAUSES damage during surgery
• chamber dilatation
• myocardial hypertrophy
• meds, anes agents,
  electrolytes

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ARRHYTHMIAS

• Supraventricular and sinus node
• - intra-atrial surgery
• - elevated RA pressure
• AV node and prox conducting tissue
• VSD repair
• AV septal repair
• TOF
• Ventricular
• Pressure loaded eg AS
• Chr RV volume and pressure load eg TOF
• Tachyarrhythmia and vent dysfn is dangerous

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HYPOXEMIA/CYANOSIS

• 2 causes
• - R to L shunt
• - Admixture (QpQs 11 sats 75-85)
• 2 outcomes
• - Thromboembolism
• Chr hypoxemia polycythemia
  viscosity
• - Coagulopathy
• Correlates with Hct
• Due to platelet and factor deficiency

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PULMONARY HYPERTENSION

• Unrestricted L to R shunt PBF PAP
• Affects ventilation
• Enlarged vessels obstruct airways
• Enlarged LA venous congestion
• Produces structural changes in pulm vessels
• medial hypertrophy, necrotizing arteritis
• PVOD
• PHT (labile vs fixed, severity)

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ENDOCARDITIS

• Prophylaxis for all EXCEPT
• Secundum ASD
• Repaired ASD, VSD, PDA gt 6 months and no residua
• Resp flex.bronchoscopy, BMTs
• GIT TEE, endoscopy
• GUT circumcision, urethral cath
• Cardiac cath, angioplasty

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ENDOCARDITIS

• Above diaphragm
• Ampi or Amoxicillin 50mg/kg (PO 1hr, IV 30m)
• Clindamycin 20mg/kg (PCN allergic)
• Cefazolin 25mg/kg (mild PCN sensitivity)
• Below diaphragm
• Ampi 50mg/kg Gent 1.5mg/kg
• Ampi or Amox 25mg/kg 6hr later (high risk)
• Vanc 20mg/kg Gent 1.5mg/kg (PCN allergic)

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PREOP ASSESSMENT

• Concerns on history
• Failure to thrive, sweating, dyspnea (CCF)
• Poor exercise tolerance
• Rec. chest infections
• PHT
• Severe AS syncope, lethargy
• Uncorrected TOF cyanosis, squatting
• ? Prior surgery eg. Shunts, Fontan etc

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PREOP ASSESSMENT

• Examination
• Active/well-nourished vs ill-looking
• Cyanosis, sweating, tachypnea, dyspnea
• Venous distension, hepatomegaly
• Murmurs, crackles and wheezing
• Check pulses
• Neurological damage (CPB, paradoxical emboli, and
  cerebral abscess/infarct)
• Airway

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PREOP ASSESSMENT

• Labs Hct, K
• ECG age-related, best evaluated by card.
• ECHO recent
• type and severity of lesion
• ventricular function
• pulmonary pressure and O2 response
• Close collaboration with cardiologist invaluable

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INDICES OF CRITICAL IMPAIRMENT

• Chronic hypoxemia (sat lt 75)
• QpQs gt 21
• LV or RV outflow gradient gt 50 mmHg
• Elevated pulmonary vascular resistance
• Polycythemia (Hct gt 60)

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PREOP

• Limit fasting
• Cardiac meds omit diuretic
• Appropriate premed
• Endocarditis prophylaxis

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GENERAL APPROACH

• R to L shunt
• Avoid IV air No N2O
• IV volume
• PVR (already low)
• SVR (phenyl 10mcg/ml 1-4mcg/kg)
• Inhalslower

• L to R shunt
• PVR for large shunt
• inotropy dynamic
• IV fluid obstruction
• IVslower

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End of Part 1